Exploring the effect of environmental temperature on calling behaviour in two island frog species - Supplementary Tables.

Global warming is leading to increased air temperatures and tropical island fauna are particularly vulnerable to these changes. We need a better understanding of how temperature variation affects biological traits in animals, particularly those involved in reproduction. In anurans, vocalisation is an integral part of reproductive behaviour. This study aimed to fill gaps on how environmental temperature may affect calling behaviour in populations of two tropical island frogs, one with a narrow geographical and elevational range (~170 km2; 0-575m): Pristimantis charlottevillensis, and the other with a wider range (~2600 km2; 0-940m): P. urichi. We used passive acoustic monitoring to sample ten sites in 2023 and 2024. From these recordings, we extracted call rate and call duration, and used Generalised Linear Mixed Models to evaluate whether air temperature affected call properties in populations of both species. We found that increased air temperature reduced call rate in both species, while having no significant effect on call duration in either species. Our results showed two closely-related species with differing environmental ranges display similar responses in calling behaviour to environmental temperature, with unknown reproductive impacts, emphasising the need to consider future temperature changes in conservation planning for this hyper-diverse genus containing many red-listed species.